THE AMERICAN DESERTS
flora and is centrally located with refer
ence to the deserts of Texas, Chihua
hua, New Mexico, California, and So
nora. The town has a population of
io,ooo, who have presented the labora
tory with a convenient site and have
aided it in many other ways.
Tucson, for centuries before the land
ing of Columbus, was one of the per
manent settlements of the ancestors of
the Papago Indians of today. These
Indians were partly migratory, moving
southward in autumn to hunt in the
sierras during the winter and returning
in spring to replant their crops.
They scoured the Sonoran plains for
chance water-holes, as well as more
permanent waters, carrying religiously
hoarded seeds; they chased rainstorms
seen from commanding peaks for scores,
if not hundreds, of miles, and wherever
they found standing or running water,
or even damp soil, they planted their
seeds, guarded and cultivated the grow
ing plants with infinite patience, and,
after carefully harvesting the crop,
planted some of the finest seeds as ob
lations and preserved others against the
ensuing season, so that the crop plants
were both distributed and improved
from year to year.
It was among the desert hills west of
Torres that the writers had an opportu
nity to see a Papago Indian extract from
a bisnaga(Echinocactusemoryi), or barrel
cactus, water with which to quench his
thirst. He cut the top from a plant
about five feet high, and with a blunt
stake of palo verde pounded to a pulp
the upper six or eight inches of white
flesh in the standing trunk. From this,
handful by handful, he squeezed the
water into the bowl he had made in the
top of the trunk, throwing the discarded
pulp on the ground. By this process
he secured two or three quarts of clear
water, slightly salty and slightly bitter
to the taste, but of far better quality
than some of the water a desert traveler
is occasionally compelled to use. The
Papago, dipping this water up in his
hands, drank it with evident pleasure
and said that his people were accus
tomed, not only to secure their drink
ing water in this way in times of ex
treme drouth, but that they used it also
to mix their meal preparatory to cook
ing it into bread.
WHAT IS A DESERT?
The current conceptions of deserts are
neither adequate nor correct if the de
scriptions in the best dictionaries and
cyclopedias are to be taken as an index.
A work of wide circulation and use de
fines a desert as "A region that is wholly
or approximately without vegetation.
Such regions are rainless, usually sandy,
and commonly not habitable."
The insufficiency of the above descrip
tion rests upon faulty observations and
upon the failure to recognize the fact
that the habitability of a region is no
criterion of its arid character. The de
velopment of modern methods of trans
portation has made possible the mainte
nance of dwellings and towns with a
considerable population at one or even
two hundred miles from the nearest
supply of water. Even such facilities
are not necessary to the sustenance of a
population in deserts of the most extreme
type, as illustrated by the Sahara, which
has a population of two and a half mil
lion people. So far as the vegetation is
concerned, the actual number of indi
viduals is much less than on a similar
area in a moist climate. This, in fact,
is one of the chief characteristics of a
desert, but it would not be safe to esti
mate the total number of species much
below the average number. Lastly, be
it remembered that local topography has
but little influence on the desert char
acter of a region. Sandy flats, plains,
valleys, and rocky hills reaching to such
altitudes as to become mountains are in
cluded in some desert tracts. It follows
as a natural consequence of the sparse
vegetation as one factor that the surface
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